1. Field of the Invention
The present invention relates to a method and apparatus for image forming, and more particularly to a method and apparatus for image forming capable of increasing maintenance efficiency with a structure in which an operator can easily check amounts of ink remaining in ink cartridges.
2. Description of the Background Art
A background inkjet recording apparatus is generally compact and convenient for color image reproduction and therefore it has been widely used in a form of various types of image forming apparatuses such as a printer, a facsimile machine, a copying machine, a plotter, and so on. In such a background inkjet recording apparatus, a plurality of recording heads are provided for different colors (e.g., yellow, magenta, cyan, and black) and eject ink drops of different colors onto a recording medium (e.g., a recording sheet) so as to record a color image on the recording medium.
The background inkjet recording apparatus is generally provided with a convenient ink cartridge system in which an ink tank for each color ink is separated into a main tank and a sub tank connected to each other with a flexible tube. The main tank includes an ink cartridge and is exchangeable for replacement, and the sub tank is disposed on the recording head. The main tank is configured to communicate with the sub tank through the flexible tube so that ink is supplied from the main tank to the sub tank when an amount of ink in the sub tank decreases.
The above-described main tank is typically provided inside the background inkjet recording apparatus, and therefore is not easy for an operator to predict a time to exchange the main tank.